The 12-person panel said Chauvin was guilty of second- and third-degree murder and second-degree manslaughter.
The jurors came to their decision after 10 hours of deliberations and some three weeks of testimony, which included dozens of witnesses.
The judge revoked Chauvin's bail and remanded him into custody immediately after the verdict was announced.
Chauvin faces up to 40 years in prison on the second-degree murder charge, up to 25 years on the third-degree murder charge and up to 10 years on the manslaughter charge. The judge will determine the punishment and whether the sentences should be served back-to-back or concurrently.
The judge said he'd set a sentencing hearing in about eight weeks.
Ben Crump, who was part of the Floyd family's legal team, said the verdict represented a "turning point" for accountability in law enforcement.
"Painfully earned justice has arrived for George Floyd's family and the community here in Minneapolis, but today's verdict goes far beyond this city and has significant implications for the country and even the world. Justice for Black America is justice for all of America," he said.
"But it does not end here. We have not forgotten that the other three officers who played their own roles in the death of George Floyd must still be held accountable for their actions, as well."
Other former officers -- J. Alexander Kueng, Thomas Lane and Tou Thao -- face charges of aiding and abetting second-degree murder and manslaughter. They will be tried separately from Chauvin.
All four men were fired the day after Floyd's death.
President Joe Biden said Tuesday he's spoken with Floyd's family ahead of the verdict.
"I can only imagine the pressure and anxiety they're feeling," Biden told reporters.
"I'm praying the verdict is the right verdict."
The verdict comes some three weeks after the beginning of testimony, which included dozens of witnesses.
Prosecutors called experts and fellow officers who said Chauvin used excessive force outside of police procedures and that Floyd died of a lack of oxygen. Defense attorneys pointed to Floyd's pre-exiting heart condition and drug use as being behind his cause of his death -- cardiac arrest.
The tragedy sparked worldwide protests against racial bias and police brutality and forced many law enforcement agencies to review and reform their policies on use of force.
Authorities in Minneapolis and in other major U.S. cities have prepared for potential protests in reaction to Tuesday's verdict.